A polycarbonate resin is excellent in the mechanical strength, the electrical properties, the transparency and the like, and is widely used as an engineering plastic in various fields such as electric and electronic equipment fields and automobile fields. In recent years, in such application fields, reduction in thickness, downsizing and weight saving of molded article are in progress, and further improvement in the performance of materials to be molded is required. However, a conventional polycarbonate resin made of bisphenol A as a material has not necessarily been sufficiently excellent in the surface hardness. Particularly in outdoor use applications, as the hardness is insufficient, an additional treatment such as hard coating treatment has been applied to the surface in many cases.
Accordingly, development of a polycarbonate resin having a high surface hardness has been desired, and several proposals have been made.
For example, Patent Documents 1 and 2 propose a method for producing a polycarbonate or a copolycarbonate excellent in the surface hardness by using a bisphenol different from bisphenol A as a monomer.
Patent Document 1 discloses to carry out hard coating by a hardened coating film comprising a compound having at least two ethylenic unsaturated bonds and urethane bonds in the same molecule.
Patent Document 2 proposes a copolycarbonate resin comprising at least two types of aromatic dihydroxy compounds, as a method of increasing the hardness.
Further, Patent Document 3 proposes a method of bonding different types of polymers on a molded specimen such as hard coating treatment, to form a multilayered structure.
Further, Patent Document 4 proposes to improve the surface hardness of a blended material of a polycarbonate resin derived from dimethyl bisphenol cyclohexane and a bisphenol A type polycarbonate resin.